1. Field of Invention
The present invention relates to braking systems for use with small utility vehicles such as riding lawn mowers, lawn tractors and the like, specifically, disc braking systems.
2. Description of the Related Art
Typically, small utility vehicles and implements, such as riding lawn mowers, lawn tractors, and snow throwers, contain an internal combustion engine that supplies drive power in the form of rotary mechanical motion to the input of a transaxle. In some cases the transaxle then transfers this mechanical motion through a gearbox and then to a differential, which splits the rotary mechanical motion between two axles at the output of the transaxle. The axles each terminate with connections to wheels that engage the ground to drive the vehicle or implement. Braking systems are utilized with such vehicles to allow an operator to slow or stop motion of the vehicle, and to prevent runaway implements and resultant injuries.
Some previous braking systems have employed braking mechanisms that are mounted completely within the transaxle casings. A problem with such braking mechanisms is that the braking mechanisms must be assembled contemporaneously within the transaxle casings, and therefore any design changes in such braking mechanisms necessarily require additional complementary design changes in the transaxle casings. A further problem with these braking mechanisms is that the transaxle casings must be separated and the transaxle partially disassembled in order to access the braking mechanisms for servicing. In addition, locating the braking mechanisms within the transaxle casings increases the likelihood that the brake disc will be contaminated by oil, grease or other lubricants used to lubricate the gears and shafts within the transaxle, and may adversely affect brake performance.
Another previous braking mechanism utilizes a brake housing, which is mounted on the exterior of the transmission and includes a brake disc and brake pucks located externally of the transmission, and a brake lever, located on the exterior of a brake housing, which rotates to move a friction puck into braking engagement with the brake disc (U.S. Pat. No. 5,195,386). Such a braking mechanism structure allows the brake to be located externally of the transmission, but requires the use of several components for actuation of the brake, thereby raising the cost and complexity of the braking mechanism. Furthermore, such a structure requires additional assembly steps, thereby limiting the capability of the braking system being shipped with the transaxle and limiting the possibility of installation of the transaxle into a vehicle without requiring the vehicle manufacturer to conduct additional assembly of the transaxle, or the possibility of xe2x80x9cdrop-inxe2x80x9d installation of a transaxle including the brake mechanism to a vehicle.
What is needed is a braking system for a small utility vehicle or implement that effectively stops, slows, or prevents motion of the vehicle. A further need is for a braking system that contains braking mechanisms mounted such that the braking mechanisms are readily accessible for servicing by not being internally disposed within the transaxle casing, cannot be contaminated by oil, grease, or other lubricants from within the transaxle casings, and can be shipped with the transaxle as a single unit to a final vehicle assembly location for xe2x80x9cdrop-inxe2x80x9d installation to the vehicle.
The above-mentioned and described shortcomings are overcome by providing a braking mechanism which is mounted externally of the transaxle casing and which includes a removable cover, thereby providing access for servicing and preventing contamination by oil, grease, or other lubricants. Furthermore, the braking mechanism may include a portion formed with the transaxle casing such that the braking mechanism may be combined with the transmission into a single unit.
The present invention provides a transaxle for a small utility vehicle or implement, including a casing, at least one rotatable shaft disposed in and extending from the casing, at least one brake disc rotatably fixed to the rotatable shaft for rotation therewith, and at least one braking mechanism with at least a portion of the braking mechanism being externally mounted on the casing proximate the rotatable shaft. The braking mechanism includes at least one friction puck disposed proximate the brake disc, and a brake shaft including a cam surface having a longitudinal edge, wherein the brake shaft has an engaged position in which the longitudinal edge is in operative engagement with the friction puck and the friction puck is in pressing engagement with the brake disc and a disengaged position in which the longitudinal edge is out of operative engagement with the friction puck.
The present invention further provides a braking mechanism for a transaxle in a small utility vehicle with at least a portion of the braking mechanism being externally mounted to the transaxle. The braking mechanism includes a brake disc, at least one friction puck disposed proximate the brake disc, and a brake shaft including a cam surface having a longitudinal edge, wherein the brake shaft has an engaged position in which the longitudinal edge is in operative engagement with the friction puck and the friction puck is in pressing engagement with the brake disc and a disengaged position in which the longitudinal edge is out of operative engagement with the friction puck.
The present invention further provides a transmission for a vehicle including a casing, at least one rotating shaft extending from the casing, a brake disc rotatably fixed to the rotating shaft for rotation therewith, and at least one braking mechanism. The braking mechanism includes a brake housing with at least a portion of the brake housing being externally mounted on the casing, at least one friction puck disposed proximate the brake disc, and a brake shaft including a cam surface having a longitudinal edge. The brake shaft has a first, rotated position in which the longitudinal edge is in operative engagement with the friction puck such that the friction puck is in pressing engagement with the brake disc, and a second position wherein the longitudinal edge is not in operative engagement with the friction puck and the cam surface is disposed parallel to the friction puck.